JP2829549B2 - Lubricants for civil engineering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of laying underground a laid pipe such as a fume pipe by a propulsion method, a method of driving a steel pipe pile or the like into the ground, or a method of setting a caisson. In order to reduce the propulsion resistance of objects such as pipes, piles, caisson, etc., the method of injecting into the boundary between the outer surface of the object and earth and sand, gravel, etc., pile pulling out, lubrication for civil engineering used for laying caisson, etc. Agent.

[0002]

2. Description of the Related Art The propulsion method is a method used when a concrete or cast iron pipe is pushed into the ground with a hydraulic jack to construct a power line, a telegraph telephone line, water supply and sewage, etc., and does not involve ground excavation. It is often used because it has relatively little impact on traffic and commercial activities. In this method, the excavation direction can be corrected by own jack operation, and since a face retaining mechanism is provided for stabilization of the face, safety in construction is high and suitable for large-diameter construction. In these methods, since the contact area between the propulsion pipe and the earth and sand, gravel, etc. increases according to the propulsion distance, it is common practice to reduce the propulsion resistance by injecting a lubricant.

Conventionally, as a lubricant for propulsion, bentonite, mineral oil, sodium polyacrylate, CMC (carboxymethylcellulose) and the like mixed with water have been used, for example, in Japanese Patent Publication No. 48-1906. It is described in the gazette.

As a technique for mixing and dispersing a mineral substance and a polymer emulsion, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 6994 / 59-33381.

[0005] Further, as a technique of using a superabsorbent resin by blending mineral oil, organic paste, surfactant and oils as required, JP-A-55-75483 and JP-A-2- For example, there is one disclosed in JP-A-13697.

[0006]

However, the methods disclosed in JP-B-48-1906 and JP-A-59-33381 disclose the use of a mineral material such as clay in the propulsion method. To disperse, an aqueous suspension containing a water-soluble polymer (dispersant) having a high anionization rate typified by sodium polyacrylate or the like is used, and the mineral substance has special physical properties such as bentonite. Is required, and it is inconvenient to transport or store the clay. In addition, bentonite and the like tend to become mamako when dispersed in water, and workability is poor. Furthermore, bentonite mud has a strong thixotropy, and there is a problem that a large force is required when the mud is pushed again after a long period of work such as after a holiday is stopped.

[0007] Further, the lubricant of JP-A-55-75483 has a problem that the mixing and preparation operations of various chemicals are complicated, and the preparation requires much time.

In Japanese Patent Application Laid-Open No. 2-13697, superabsorbent resins are used. However, these resins are in the form of fine powder, and when a water dispersion is prepared, the working environment due to scattering of the fine powder is reduced. In addition to the deterioration, there is a problem that it takes time and effort to inject the chemical at the time of construction, and that it takes time for the chemical to react with moisture to form a gel. Furthermore, since it is not water-soluble because it is partially crosslinked, the load at the time of injection tends to increase.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and includes a propulsion method, a pile driving and pulling method,
As an anti-friction agent for civil engineering used in the construction of caisson, etc., it does not use mineral substances such as clay, it has a water stopping effect, and even after a long period of inactivity, minerals such as clay as conventional lubricating agents An object of the present invention is to provide an anti-friction agent for civil engineering that can be satisfactorily operated immediately after the start of the operation without increasing the initial indentation pressure due to its quality.

[0010]

The present invention is configured as follows to achieve the above object. That is,
The present invention relates to an acrylamide / acrylate copolymer having an anionization ratio of 15 to 40 mol%.
The present invention relates to a civil engineering lubricant obtained by dissolving parts by weight in 100 parts by weight of water.

In this lubricant for civil engineering, the acrylamide / acrylate copolymer has an intrinsic viscosity of 15 dl / g or more at 25 ° C. in 1N saline.

This civil engineering lubricant obtains an acrylamide / acrylate copolymer by inverse emulsion polymerization.

This civil engineering lubricant is used in a propulsion method, a pile driving and drawing method, or a caisson sinking method.

This lubricant can be prepared by dissolving the polymer powder in water. However, the oil contained in the lubricant helps to reduce friction and the polymer dissolving operation is easy. As the polymer for a lubricant used in the present invention, an emulsion obtained by inverse emulsion polymerization is desirable.

In the lubricant for civil engineering according to the present invention, the polymer may be copolymerized with another monomer (for example, acrylamido-2-methylpropanesulfonate) as long as the properties are not impaired. In this civil engineering lubricant, the water that dissolves the polymer does not exclude the inclusion of some mineral substances, and can be used by dissolving it in low-concentration mud that is easily available at the construction site. And the anionization rate of this polymer is 2
0-35 mol% is particularly preferred.

[0016]

The lubricant for civil engineering according to the present invention is constituted as described above and operates as follows. That is, the present invention has an anionization ratio of 15 to 40 mol%,
Inherent viscosity in normal saline is 15 at 25 ° C
It is a civil lubricant made by dissolving 0.1 to 1.0 parts by weight of an acrylamide / acrylate copolymer having a dl / g or more in 100 parts by weight of water. The above aqueous polymer solution can be used alone as a civil engineering lubricant without the need for a water stopping action.

The water stopping effect in the propulsion method, the pile driving and pulling method, the caisson setting, and the like is exerted by the aggregation of a small amount of silt clay in the gravel layer. Even so, it is possible to prevent dissipation. The lubricant for civil engineering according to the present invention does not contain a mineral substance as in the prior art, and does not use a cross-linking agent such as a superabsorbent resin. The use of polymers having the following as lubricants is a new finding.

Further, if the civil engineering lubricant contains oil derived from the emulsion, an oil film is formed between the outer wall of the object such as a pipe and a pile and the gravel, that is, at the boundary surface, and the propulsion resistance of the object to the gravel is reduced. Reduce friction.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings, a description will be given of a lubricating agent for civil engineering used in a propulsion method, a pile driving method, a drawing method, or a caisson laying method according to the present invention. In FIG.
An example in which this civil engineering lubricant is used in a propulsion method is shown. In the propulsion method, for example, a stratum 5 such as a sand layer, a fine sand layer, a gravel layer, and a clay layer is excavated by a shield machine 1 provided with a bit, that is, a cutter 3, and a pipe 2 such as a temporary pipe or a fume pipe is inserted into the excavated hole.
Is press-fitted and the pipe 2 is buried in the excavation hole 7. At this time, in order to push the pipe 2 into the excavation hole 7, the pipe 2 is pushed in by the jack 4. In this propulsion method, an important issue is how to reduce the frictional resistance of the contact surface between the outer surface of the pipe 2 and the stratum such as gravel around the pipe. The lubricant for civil engineering is supplied to the shield machine 1 or the pipe 2 through the lubricant injection pipe 6 by the operation of the lubricant supply pump 8.
Is injected between the pipe 2 and the excavation hole 7 from the injection port 9 provided near the foremost portion of the pipe, and the press-in resistance generated between the pipe 2 and the excavation hole 7 is reduced to promote the pushing of the pipe 2.

Next, specific examples of the lubricant for civil engineering according to the present invention will be described. Adjust the sample to make sample 1 to sample 1.
I made one. Samples 1 to 11 were prepared by synthesizing acrylamide / sodium acrylate copolymers having the physical properties shown in Table 1 by ordinary reversed-phase emulsion polymerization. At this time, the polymer concentration in the emulsion is 30% by weight.

[Table 1]

Next, a liquid penetration test was performed on Samples 1 to 11 prepared as described above. Gravel containing 9% by weight of silt clay was filled in a pipe having an inner diameter of 50 mm and a length of 100 mm, and the time required for passing the aqueous solution of each sample at a pressure difference of 50 atm was measured. Table 2 shows the results.

[Table 2]

Further, a tube propulsion test using the above-mentioned samples 1 to 11 was conducted. 1.35m in diameter and 2.
While connecting the 43 m fume pipe, the pipe was pushed by a jack. The area around the fume pipe is a gravel layer, with a gap of about 2 cm between the pipe and the gravel layer.
The pipe was pushed in by jack while pouring lubricant for civil engineering from various places. The jack pressure at a pipe length of 200 m was set to 100 with the aqueous solution of sample 5 (polymer concentration: 0.3%).
It was 200 t when injected at a rate of liter / m. On the other hand, when the polymer of Sample 9 was used, it was impossible to push the fume tube with the jack. Further, when the lubricant for civil engineering according to the present invention was used, the pushing pressure at the start of the pushing after the holidays did not increase. When the sample 10 and bentonite were used in combination, the indentation pressure at the beginning of the holiday was increased to 300 t or more.

[0023]

The lubricant for civil engineering according to the present invention is constituted as described above and has the following effects. That is, this civil engineering lubricant has an anionization ratio of 15 to 40 mol%, and in particular, an acrylamide / acrylate copolymer having an intrinsic viscosity of 15 dl / g or more at 25 ° C. in 1N saline. 0.1 to 1.0 parts by weight of
Since it is dissolved in 00 parts by weight of water, it exhibits a water stopping effect without using minerals such as clay as in the past, and like a conventional lubricant even after a long rest period, There was no trouble that the initial indentation pressure increased due to the solidification of the clay and minerals contained in the lubricant, and the pipes, piles, and other objects immediately after the resumption of the work of pushing in the pipes, piles, and other objects associated with excavation. Good anti-friction effect between the strata can be exhibited.

Further, since the civil engineering lubricant does not use auxiliary materials such as bentonite, the civil engineering lubricant is used to carry out a work such as a propulsion method, a pile driving and drawing method, or a caisson laying down operation. In such a case, the workability thereof is extremely excellent, the work efficiency can be improved, and the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for explaining an example of a propulsion method capable of using a civil engineering lubricant according to the present invention.

[Description of Signs] 1 Shielding machine 2 Pipe 3 Cutter 4 Jack 5 Formation 6 Lubricant injection pipe 9 Injection port

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Moriyaya Shikushige 3528 Higashi-Oto, Kasaoka City, Okayama Prefecture Toyo Bentnite Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) C09K 7/00-7 / 08 E21D 9/06

Claims (6)

(57) [Claims] 1. An acrylamide and acrylate copolymer having an anionization ratio of 15 to 40 mol% in 0.1 to 1.
A lubricant for civil engineering, comprising 0 parts by weight dissolved in 100 parts by weight of water. 2. The lubricant according to claim 1, wherein the copolymer of acrylamide and acrylate has an intrinsic viscosity of 15 dl / g or more at 25 ° C. in 1N saline. 3. The lubricant for civil engineering according to claim 1, wherein an acrylamide / acrylate copolymer is obtained by inverse emulsion polymerization. 4. The lubricant for civil engineering according to claim 1, which is used in a propulsion method. 5. The lubricant for civil engineering according to claim 1, which is used in a pile driving and drawing method. 6. The lubricating agent for civil engineering according to claim 1, which is used for laying a caisson.